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TY - THES AU - Chen, Junlin TI - Polymeric microbubbles for mRNA delivery and molecular imaging PB - Rheinisch-Westfälische Technische Hochschule Aachen VL - Dissertation CY - Aachen M1 - RWTH-2025-07096 SP - 1 Online-Ressource : Illustrationen PY - 2025 N1 - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University N1 - Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2025, Kumulative Dissertation AB - Microbubbles (MB) are hollow, air-filled particles that have garnered increasing attention in gene delivery and ultrasound (US) molecular imaging. In mRNA delivery, MB are used as enhancers to improve DNA and mRNA passage through biological barriers under US exposure. However, it has remained unclear whether nanocarrier-encapsulated mRNA should be administered separately (co-administration) or conjugated to MB (co-formulation). Therefore, we analyzed the impact of poly(n-butyl cyanoacrylate) MB (PBCA-MB) co-administration with mRNA-DOTAP/DOPE lipoplexes or their co-formulation on the transfection of cancer cells in vitro and in vivo. Our studies demonstrate that PBCA-MB combined with US are highly suited to enhance mRNA transfection efficacy in vitro and in vivo. Under focused US exposure, co-formulation mainly transfected (peri)vascular tissue. Compared to co-formulation, co-administration reached deeper tumor tissues, thus resulting in higher transfection efficiency. On the other hand, compared to co-administration, co-formulation induced less off-site transfection, and the transfection by the co-formulation approach was more dependent on the ultrasound trigger. Consequently, the choice between co-administration and co-formulation should be thoroughly considered based on the specific targets and objectives when delivering nucleic acids. Additionally, the development of MB-based co-formulation approaches relies heavily on bioconjugate chemistries. However, introducing functional ligands to MB surfaces has been challenging, as conventional methods for functionalizing PBCA-MB often require multi-step synthesis, leading to low MB yield, poor controllability, and limited reproducibility. In this context, we developed a novel single-step aminolysis protocol to generate functionalized PBCA-MB as ultrasound contrast agents. To comprehensively characterize this method's efficacy in introducing functional ligands to MB, actively-targeting MB were generated and we display that they were capable of binding efficiently to inflammatory endothelium under in vitro, ex vivo, and in vivo conditions for breast cancer detection. Our results demonstrated that the aminolysis protocol significantly outperformed conventional functionalization strategies (hydrolysis and carbodiimide chemistry) in terms of simplicity, higher MB yield, and improved controllability and reproducibility. This innovative method has the potential to facilitate the transition from laboratory-scale production to large-scale manufacturing, thereby reducing costs and accelerating clinical translation of MB-based technologies in both gene delivery and molecular imaging applications. LB - PUB:(DE-HGF)11 DO - DOI:10.18154/RWTH-2025-07096 UR - https://publications.rwth-aachen.de/record/1017036 ER -